Electric indicator



March 13, 1956 A. L. FlTzslMMoNs 2,738,404

ELECTRIC INDICATOR United States Patent O ELECTRIC INDICATOR Archie L. Fitzsimmons, Honoiulu, Territory of Hawaii Application November 21, 1952, Serial No. 321,837

2 Claims. (Cl. 201-43) This invention relates to devices for indicating the intake manifold pressure of internal combustion engines and more particularly to an intake manifold pressure actuated device for visually indicating whether an internal combustion engine is operating within a predetermined portion of its power range.

It is among the objects of the invention to provide an improved indicating mechanism which can be mounted adjacent an internal combustion engine and actuated by the intake manifold pressure of the engine to advise the operator of the engine whether or not the engine is operating in a predetermined desirable portion of its power range, so that the operator can, if necessary, eiect a more efficient operation of the engine by readjusting the throttle setting, shifting the change speed transmission or placing the overdrive mechanism into or out of operation in the y case of an automotive vehicle, boat or aircraft engine, or by such other means as may be available to him; which includes a visual signal element, such as an electric lamp, and intake manifold pressure operated mechanism, including a variable resistance device connected into the lamp circuit, effective to cause the lamp to be brightly illuminated when the engine is operating outside of a predetermined desirable portion of its power range and to be dimly illuminated or extinguished when the engine is operating within the desirable portion of its power range; which is adjustable for different engines and different operating conditions; which can be connected to an engine with no material modification of the engine construction; and which is simple and durable in construction, economical to manufacture, easy to install, and effective in operation.

Other Vobjects and advantages will become apparent from a consideration of the following description and the appended claims in conjunction with the accompanying drawing wherein:

Figure l is a side elevational View of manifold pressure indicating mechanism illustrative of the invention;

Figure 2 is a medial longitudinal cross sectional view of the mechanism illustrated in Figure 1;

Figure 3 is an end elevational view of the mechanism illustrated in Figure l looking at the left-hand end of the mechanism as illustrated in this` figure; and

Figure 4 is a diagrammatic view of the indicating mechanism showing the application thereof to the intake manifold of an internal combustion engine.

With continued reference to the drawing, and particularly to Figure 4, the numeral 10 generally indicates an internal combustion engine having an intake manifold 11 provided with a charge heating chamber 12 and to which a carburetor 13 is operatively connected.

It is well known that the power output of internal combustion engines, such as are commonly used for the propulsion of automotive vehicles, boats and aircraft and for stationary power plants, is directly proportional to the operating speed of the engine and the engine intake manifold pressure and that, when the manifold pressure is in the lower portion of the range of manifold pressures,

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of the engine when the engine is operating at manifold pressures above the selected lower portion of the range of manifold pressures consistent with efficient engine operation.

The indicating mechanism comprises an expansible chamber device, generally indicated at 15, which is illustrated as comprising a hollow housing 16 of rigid con' struction consisting of a pair of bell shaped parts 17 and 18 secured together with their open ends in mutually registering relationship by suitable means, such as screws 19 extending through registering apertures in superposed annular anges 20 and 21 provided on the housing parts 17 and 18 respectively, at the open ends of these housing parts.

A flexible diaphragm 22 extends transversely of the interior of the housing 16 and is marginally clamped between the housing flanges 20 and 21.

The housing 16 is provided with a centrally disposed hollow tubular guideway 23 extending therefrom in a direction away from the housing part 17 and at its end remote from the housing part 18 the guideway 23 is pro-vr vided with a combined valve and tube fitting 24 having a bore communicating with the interior of the tubular guide 23 and an adjustable valve screw 26 intersecting the bore to variably restrict the area or" the bore. The fitting 24 is connected by a suitable conduit 26 to a fitting 26' secured in an aperture in the engine intake manifold 11, so that the interior of the tubular guide formation 23 is in communication with the interior of the intake manifold.

The housing part 17 is provided with a centrally located aperture 28 and a shaft 29 extends slidably through the aperture 28 and through a centrally disposed aperture 30 in the diaphragm 22. The portion of the shaft 29 extending through the diaphragm is reduced in diameter and externally screw threaded, as indicated at 31, and clamping nuts 32 and 33 are threaded onto the shaft at respec` tively opposite sides of the diaphragm and secure the diaphragm to the shaft for movement of the shaft by the diaphragm when the diaphragm is moved by pressure variations in the portion of the housing 16 at the side of the diaphragm adjacent the tubular guide formation 23. The diametrically reduced portion of the shaft 29 extends beyond the diaphragm 22 and is slidably received in an aperture 34 provided in a guide spider 35 mounted in thel tubular guide formation 23.

As its end disposed outwardly of the housing part 17 the shaft 29 is externally screw threaded, as indicated at 36, and a washer 37 receives the shaft 38 at the inner end' of the screw threaded end portion 36 of the shaft. A compression spring 38 surrounds the shaft 29 between the washer 37 and the adjacent surface of the housing part 17, and a nut 39 is threaded onto the screw threaded portion 36 of the shaft and bears against the washer 37 at the f side of the washer remote from the spring 38.

A movable contact carrier in the form of an angle arm 40 has two legs disposed substantially perpendicular to each other and one of these legs is provided with an aperture receiving the shaft 29 at the side of the nut 39 remote from the washer 37. A second nut 41 is threaded onto the screw threaded end portion 36 of the shaft 29 and bears against the side of the one leg of the angle arm 40 remote from the nut 39 to clamp the angle arm between the nuts 39 and 40 and thus rigidly secure the angle arm on the shaft 29.

angle bracket'42fis-secured at one end to the housingpart 17 and projects outwardly from this housing part in spaced and substantially parallel relationship to the portion of the shaft 297projecting out of the same housing'part;

Anelongated resistance coil 43 is mounted'oni-the"angiey bracket 42 and extends longitudinally'of thefangle bracket v andamovablecontact 44; is carried' bythe other legofthe anglegarm 40in position to engage vthe 'resistancefcoil 431% When the intake manifoldv pressure is within" apredetermined'p'ortion-'nearfthe"-lower end' of -the' pressuret range, Y thexdiaphragm'ZZ'isdrawnV towardthe tubular guide formation 23, as:illustratedinFigurev 2, movingith'e shaft 29sy against the force" of spring 3S v inf-afdirection 'toward-fl the combined-.evalve` tand" tube tting "2413v Thisposition-s1 the movable contact 44 olf of the coil 43, as illustrated" inFgurerZ, oronvthefend ofthe coil:fnearestrthev housing` 16. Ass'thefmanifoldpressre increases, the"spring`!38f moveslthe--shaft 39'in1a' direction to move themovable contactalongihecoil 43frorn' `the end of thec'oil nearest! the; housing f17 toward 'theopposite end of -th'e resistance The engine" 1'0:A isprovided with ai suitable' i sourcef of electrical energy,vsuchas the storage-battery 45; andfis also providedwithanignitionfcontrollingswitch 46'; one

side of which is connected to the battery 45 by an elec-y trical 'cont iuctor4'7;V Aconductor 48`l leads fromftheother si'de'poff the switch 46 to theA engine. ignitionsystemland` anothed conductor 49also Yleads from the same' sideof the switch asfthatffromv which thef conductor' 48T extends tQ- the movabler'contact v44.A A conductor 50 leads from the end'offtheresistance coil 43` remote from the housing 16 toalampbulb socket 51 mounted at a location readilyfl visible to thev operator ofthe engine or driver of the'y associated vehicle, as onthe instrument board off a vehicle,"- andthe other sideof the battery 45 is provided-witha groundconnection" 52; the side of the battery 45 remo'te from`the;y conductor 47 being grounded, asv indicatedy atf 53: ,K A lamp bulb 55 is mounted in the'socke't'S.

Whenfthomovable contact 44 is at theendofthe'coil 43 nearest the'housing-l,` the lamp 'circuit'is' brokenarid the lamp'isl extinguished,=and when this movable' contact isponpthe end ofi the'resistancefcoil nearest the housing-- theu lamp ispnlyg dimly illuminated, since' theflampfcirc'ui't then includes: all,for most ofthe resistance"y c'oil when the pressure inthe'intake manifold vacuurrifisilow; the lampisA only dimly' illuminated or completely extin# Vguished As the pressure' inA theV intakel manifoldl r-i'sesf andthe'rnovahle'contact 44' is movedalong.v the "resistance coil' 43, in1a direction-away from the housingdg-lessl'a'i'id lessi-of the resistance coil' is. included in tlieflam'pcircuit and the lam-pis progressively more brilliantly illu'riiiiitefd asgthe movable Contact, 44 is moved from thee'nd of theresistance coil; nearest' the housingy 1f," to" the"v endthe' resistance:coilfurtliestfroni the housing. As lthe lanip Cit strictive, the scope of the invention being indicated by the appended claimsrather thanhyVtheforegoingdescripe tion, and all changes which come Within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

What is claimed is:

l. A pressure indicating device comprising a hollow housing consisting of a pair of bell shaped parts having their open ends in mutually registeringrelationship, a diaphragm interposedbetween and secured to the open ends of said parts, a hollow tubular guideway exteriorly of one of said parts and having one end secured to said one part, aV combined 'valve and tube ttingconnectedn communication with theother end ofl said guideway adapted to be connected to a source of pressure, a guide spider mounted within said guideway adjacent said one end thereof, a shaft extending through said pair of parts and diaphragm and slidably supported in said spider and the! adjacent-wally portion of the other of saidpartsfand having one f end'Y inwardly lof and adjacent the'k other end of saidguideway1and having a? portion adjacent `tl"1"e"othei f end projectingfexteriorly oftheotherof said parts," said diaphragm' being secured to said shaft for5 movementA therewith, a bracket positionedeXter-iorly of sai'ti-otli'er` part and-extending parallel tothe projectingendportion of said shaft and carried: by'said otherpart,l anranfglel bracket having oneleg fixed to the projecting end portion' ofsaid shaft and having the other` legp'arallel to'said bracket, la resistance coil on saidlbracket;V andam'ovable'- contact' carried'by said one legofsaidangle'bracket and engageable'with said-coil.y

2, A pressureindicating device-comprising'afhollow housing'consistingv of a-pair of bell shaped-partsf'having their open ends in mutually registering relationship; afdia'" i adjacent wall portion ofthe other' of said npartsarid'laving'-y one end? inwardly of andfadjacent'theotherend of said* guideway` and having' a portion adjacent the other* endl projecting'.exteriorly'of. the'othe'r of: said parts; sai'ddiav ph'r-agmf beingl secur'e'dto'V said shaftf'or movementtl'i'ere with,v a' bracket positioned exterio'rly of'I said otlier'part and extending parallel to the projecting end portio'n of-j saidY shaft'and-carrlied by said`oth`e'r part; an angle'y bracket havih'gtone" leglxedtb the projecting end'l portionofsaid2 shaft. and having the: other leg parallel to' said bracket,v a resistance coil on said bracket, a movablecontaet'carriedi by sa'idf one le'g ofi s'aid' anglebracket'f and engageable with; said coil, and spring" means operatively* connectedi to the? projecting' end'l portion of said'- sliaft for biasing said one end of said shaft away from said fitting:

Drabin L .7 Ian.' 1.5, 1935 

